Automatic door for elevator hatchway openings



- June 10,, 1941.. N. GUILBERT, JR 2,245,072

AUTOMATIC DOOR FOR ELEVATOR HATGHWAY orrmmes Filed July 2, 1940 INVE/V7'01? w/ TNESS Wren/vs) Patented June 10, 1941 AUTOMATIC DOOR FORELEVATOR HATCHWAY OPENINGS Nicholas R. Guilbert, Jr., Chestnut Hill, Pa.

Application July 2, 1940, Serial No. 343,521

Claims.

This invention relates to means for automatically actuating the doorsfor the openings in elevator hatchways, and is particularly adapted foruse with elevators of the character commonly employed for transportingarticles of merchandise and the like between different floor levels inrestaurants, retail stores and generally similar establishments andwhich are known as dumb-waiters.

In such elevators the car is arranged to travel in a vertical hatchwayhaving spaced openings proximate the different floor levels throughwhich access can be obtained to the car when in registry therewith, adoor being associated with each opening for closing it when the car isin some other position.

When the doors are arranged for independent manual operation they arefrequently not closed when they should be because of carelessness orsome other reason; this gives rise to accidents particularly when theupper door, as is often the case, is beneath a counter or in a generallysimilar location with its sill relatively close to the floor.Consequently some attempts have been made to provide means forautomatically closing and opening the doors at the proper times but themechanisms designed for accomplishing this purpose with which I amfamiliar are extremely complicated and therefore apt to get out oforder, while their cost is often so great as to be prohibitive. I

It is therefore a principal object of my invention to provide automaticclosure means for dumb waiter elevator hatchway openings and the likewhich are extremely simple in design and construction, inexpensive toinstall and which positively prevent the upper hatchway opening beingleft unguarded by its door save when the elevator car is in proximity toit.

Another object is to provide doors for hatchway openings located atdifferent floor levels which are counter-weighted against each other andautomatically operative in response to movement of the elevator car fromone opening to the other to prevent access to the hatchway througheither of the openings while the car is in registry with the other.

A further object is to provide doors of this character andinterconnecting and operating mechanism therefor whereby the weight ofone of the doors is utilized to actuate the other and bring it intoregistry with the adjacent opening as the elevator car moves away fromit to thereby keep that opening closed until the car during its returnthereto causes the doors to move in the opposite direction.

Other objects, purposes and advantages of the invention will hereinaftermore fully appear or be understood from the following description of apreferred embodiment of it diagrammatically illustrated in theaccompanying drawing in which Fig. 1 is a fragmentary front view of atypical dumb-Waiter elevator and hatchway including automaticallyoperating doors in accordance with the invention;

Fig. 2 is a fragmentary side elevation thereof partly broken away intovertical section;

Fig. 3 is an enlarged perspective detail of one element of the mechanismshown in the preceding figures, and

Fig. 4 is a similarly enlarged perspective detail of another.

In the several figures, like characters are used to designate the sameparts.

In the drawing, illustration of many parts of the elevator mechanismnormally essential to its proper operation is omitted since these may beof any desired character adapted for the performance of their severalfunctions and constitute no part of the present invention which isimmediately concerned only with the hatchway opening doors and theoperating mechanism therefor.

Thus Figs. 1 and 2 diagrammatically illustrate the general arrangementof a typical dumb waiter elevator of the character to which I havereferred, including an elevator car I suspended from a cable 2 in ahatchway H and vertically slidable along suitable guides (not shown)between adjacent fioors 3 and 4. The upper floor 3 may for example bethe first floor of a retail store with its hatchway opening 5 disposedbeneath a counter or the like and therefore having its lower edgeadjacent the floor level instead of raised substantially above it, whilein the basement the lower floor 4 is aligned approximately 7 with thebottom of the hatchway and the lower hatchway opening 6 spaced above thefloor at a sufiicient height to permit convenient access to it forloading or unloading the elevator car when it is in registry therewith.

It will be understood that manual or power driven car operating means(not shown) adapted for control from adjacent either the upper or thelower floor or from both, are provided for moving the car from one floorto the other, while counter-weighting means (not shown) are usuallyassociated with the car to facilitate its travel with a minimumexpenditure of energy.

hatchway. whenever the doors are moved from these nor- An upper door H]and a lower door ll respectively adapted to close the hatchway openings5 and 6 are arranged to move vertically from closed to open position andvice versa on suitable guides associated with the hatchway structure,and the doors themselves, as well as the guides, may be of anyconvenient or desired specific character; thus the details of theirconstruction require no extended description and are not illustrated, asthey form 110 part of the invention. It is preferable, however, that onedoor be somewhat heavier than the other, and in the embodiment of theinvention now being described the lower door H is the heavier.

The doors are interconnected at either side of the hatchway by means ofchains l2 or other flexible tension members the ends of which arerespectively attached to the upper .door l through the medium ofsuitable brackets I4 and to the lower door I I through the medium ofother suitable brackets I5, these several brackets being shown assecured to the respective doors adjacent their side edges, Brackets l5,however, project into the hatchway farther than brackets I4 so that thechains l2 which pass over sheaves I6 mounted for rotation on suitablesupports 1? adjacent the top of the hatchway run substantiallyvertically between the brackets and the sheaves. If desired, the sheavesmay besecured to a common shaft (not shown) at the top of the hatchwayfor unitary rotation when either is turned by its chain but this isusually unnecessary particularly when both chains are actuated in unisonbut independently as in the illustrated construction, as the doors arethen operated from a both sides at once and freedom of travel alongtheir guides thereby insured.

Through this interconnection of the doors by the chains, movement ofeither door is equal in distance but opposite in direction to movementof the other, and as lower door I l is heavier than upper door l0, theynormally occupy the positionsindicated in Figs. land 2, that is, thelower door is depressed below hatchway opening 6 while the upper door israised to registry with hatch- .wayopening-5 to prevent access throughit to the Moreover, it will be apparent that mal positions and thenreleased, lower door H will cause the upper door to rise into registrywith upper opening 5 as the lower door descends by gravity belowlowerlopening 6.

For causing the doors to automatically leave these so-called normalpositions when the elevator car is-moving upwardly into registry withthe upper-opening, means are provided whereby at the-proper time the,car assumes and'sustains part of the weight of the heavier door andthereby shifts the overbalanced relation between the doors, thusallowing the lighter one to move by gravity out of registry with opening5 and raising the other into registry with opening 6; likewise,following reversal of its movement, the car releases the doors andthereby allows the force of gravity'to move them in the oppositedirection to their normal positions.

The means to which reference has just been made preferably comprise apair of substantially cylindrical metal blocks or abutment-s 20 havtheset screws at suitablepoints adjacent the upper floor level, togetherwith actuating memblocks.

bers carried by the car and engageable with these These members includetubular sleeves 24 surrounding chains l2 and supported on brackets 25attached to opposite sides of the car, the sleeves being of such insidediameter that the chains but not the blocks can pass freely throughthem. Thus when positioned in vertical alignment with the portions ofthe chains extending between lower door brackets l5 and sheaves It, thesleeves can move along the chains with a minimum of "friction as the carmoves relatively to the chains, and as the inside diameter of thesleeves is appreciably less than the outside diameter of blocks 29, itwill be apparent that as the car rises toward upper opening 5 thesleeves engage the blocks. As the latter are secured to the chains andcannot pass through the sleeves, further movement of the car and sleevestherefore carries the blocks 25 upward to lift those portions of thechains to which they are secured and in turn lower door ll, therebyallowing upper door Hi to descend by gravity from registry with upperhatchway opening 5. Consequently when the car has moved into registrywith the latter the upper door has entirely cleared it and the lowerdoor simultaneously has been raised to registry with lower opening 6 toprevent access to the hatchway therethrough until movement of the car isreversed. 7

Upon such reversal the greater weight of door Ii maintains blocks 20 inengagement with sleeves 24 until door It has been restored to registrywith the upper opening and lower opening 8 correspondingly vacated bydoor ll. Thereafter further downward movement of the car has no eiiectupon the doors and the car is therefore acccesible through the loweropening after it aligns therewith, while the upper opening re mainsprotected by its door it.

It will thus be apparent that my invention provides simple and effectivemeans'for automatically operating the hatchway doors of elevators of theclass described in coordinated relation and in such manner that theenergy supp-lied for raising the elevator car is partially employed toovercome the preponderance of the heavier door and thereby allow thedoors to move rclativeiy to each otherin one direction while the forceof gravity alone is ultilized to similarly movethem in .the otherwhereby the upper hatchway opening is closed at all times when the caris out of registry therewith and the lower openin g is closed when thecar is at the upper one, It is therefore impossible for attendants onthe lower floor to get their heads or' arms into the hatchway while theelevator is being loaded or unloaded at the upper floor and the chanceof injury through having articles dropped down the hatchway past the caris thus-prevented; Moreover, the closing movement of the lower doorserves as a signal to the operator at the lower floor that the car isapproaching the upper one,

and thus enables him to readily determine when to deener'gize the carlifting mechanism.

While I have herein diagrammatically illustrated-and have described withconsiderable particularity one embodiment of the invention, it will beunderstood I do not desire or intend to limit or confine myself theretoin any way as changes and modifications in the form, construction andarrangement of the several parts as well as in their relationship toeach other and in their respective specific functions will readily occur'to those skilled in the art and may be .made'if desired withoutdeparting from the spirit and scope of the invention as defined in theappended claims.

Having thus described my invention, I claim and desire to protect byLetters Patent of the United States:

1. In combination with an elevator car movable between vertically spacedhatchway openings, a door adjacent and. vertically slidable into and outof registry with each opening, and means interconnecting the doors inmutually counterweighted relation operative to move each door relativelyto its opening in correspondence with movement of the other door in theopposite direction relatively to its opening.

2. In combination with an elevator car movable between vertically spacedhatchway openings, a door adjacent and vertically slidable into and outof registry with each opening, and means interconnecting the doors inmutually counterweighted relation operative to move each door incorrespondence with movement of the other door in the oppositedirection, one of the doors being heavier than the other, whereby whenreleased from registry with its opening it descends by gravity andsimultaneously through the interconnecting means raises the other doorrelatively to its opening.

3. In combination with an elevator car movable between vertically spacedhatchway openings, a door adjacent and vertically slidable relatively toeach opening, and means interconnecting the doors in mutuallycounterweighted relation in such manner that when either door is inregistry with its opening the other is out of registry with its opening,said means being operative to move each door in correspondence withmovement of the other door but in the opposite direction and one of thedoors being heavier than the other whereby when released from registrywith its opening it descends by gravity and simultaneously through theinterconnecting means raises the other door to registry with itsopening.

4. In an elevator of the class described including a car, a hatchwayhaving spaced openings, and vertically movable doors for said openings,movable tension means extending from the top of the hatchway to andinterconnecting both doors in overbalanced mutually counterweightedrelation, and means carried by the car operative during its movementtoward one opening to lift one of the doors to thereby: interrupt saidoverbalanced relation and allow the other door to move in the oppositedirection.

5. In an elevator of the class described including a car, a hatchwayhaving spaced openings and vertically movable doors for said openings,sheaves adjacent the upper part of the hatchway above both doors,flexible means passing over the sheaves and interconnecting the doors tonormally maintain them in overbalanced mutually counterweightedrelation, and means carried by the car operative during its movementadjacent one opening to sustain a part of the overbalancing load tothereby allow the doors to move in opposition to said load.

6. In an elevator of the class described including a car, a hatchwayhaving spaced openings and vertically movable doors for said openings,one of the doors being heavier than the other, a sheave adjacent the topof the hatchway, tension means passing over the sheave andinterconnecting the doors whereby the heavier door normally aliordssupport to the lighter one from the sheave through said tension means,an abutment secured to the tension means between the heavier door andthe sheave, and means carried by the car engageable with the abutmentduring movement of the car toward one opening to impose on the car apart of the weight of the heavier door and thereby enable the doors tomove in opposite directions.

7. In an elevator of the class described including a car, a hatchwayhaving spaced openings and vertically movable doors for said openings,the door adjacent one opening being heavier than the other door, amutually counterweighting connection between the doors whereby one dooris normally maintained in registry with one opening and the other dooris normally maintained out of registry with the other opening, and meanscarried by the car adapted during its upward movement to sustain part ofthe weight of the heavier door to thereby allow the doors tosimultaneously shift from said normal positions and adapted to maintainthe doors so shifted after the car is at rest in registry with the upperopening.

8. In combination with an elevator hatchway having vertically spacedopenings and a car movable therein, a pair of doors respectivelyslidable over said openings, one of said doors being heavier than theother, means suspending the doors in mutually counterweighted relationwith the heavier door normally maintaining the other in position toclose its opening, and means carried by and operative after the carreaches a predetermined point in its upward travel to overcome thepreponderance of the heavier door and enable the doors to moverelatively to each other in opposite directions.

9. Elevator hatchway opening closure mechanism of the characterdescribed comprising a pair of vertically slidable doors respectivelyadjacent vertically spaced openings in the hatchway, sheaves disposedabove the upper door, flexible tension means passing over the sheavesand interconnecting the doors, abutments fixed to the tension meansadjacent the upper door, and means carried by the elevator carengageable with the abutments during its upward movement to therebysupplement the force of gravity acting on the upper door to move saiddoor out of registry with the upper opening and the lower door intoregistry with the lower opening.

10. In combination with an elevator hatchway having vertically spacedopenings and a car movable therein, a pair of doors respectively adaptedto slide over said openings, flexible means suspending the doors inmutually counterweighted relation, the lower door being the heavier andtending to maintain the upper over its opening, means carried by the carcooperative with said flexible means when the car is travelling upwardto overcome the preponderance of the lower door and thereby enable theupper door to descend from its opening while raising the lower doortoward its opening.

NICHOLAS R. GUILBERT, JR.

